Locke's sensism was taken up by Condillac (d. 1780), who eliminated entirely the subjective factor (Locke's "reflection") and sought to explain all cognitional states by a mere mechanical, passive transformation of external sensations.

This should be frankly admitted by the defender of natural dualism, and the chief psychological problem for him at the present day is to sift and discriminate what is immediate and direct from what is mediate or representative in the admittedly complex cognitional operations of normal adult life.

It has been shown that that special form of cognitional activity which the Vedânta-texts set forth as the means of accomplishing final Release and which is called meditation (dhyâna; upâsana) has to be frequently repeated, and is of the nature of continued representation.

For by tarka we understand that kind of knowledge (intellectual activity) which in the case of any given matter, by means of an investigation either into the essential nature of that matter or into collateral (auxiliary) factors, determines what possesses proving power, and what are the special details of the matter under consideration: this kind of cognitional activity is also called ûha.